PostGIS  2.5.0dev-r@@SVN_REVISION@@
LWGEOM* lwgeom_buildarea ( const LWGEOM geom)

Take a geometry and return an areal geometry (Polygon or MultiPolygon).

Actually a wrapper around GEOSpolygonize, transforming the resulting collection into a valid polygon Geometry.

Definition at line 1406 of file liblwgeom/lwgeom_geos.c.

References LWGEOM::flags, FLAGS_GET_Z, GEOS2LWGEOM(), LWDEBUG, LWDEBUGF, lwerror(), LWGEOM2GEOS(), LWGEOM_GEOS_buildArea(), lwgeom_geos_errmsg, lwgeom_geos_error(), lwgeom_is_empty(), lwnotice(), lwpoly_construct_empty(), and LWGEOM::srid.

Referenced by _lwt_FaceByEdges(), buildarea1(), buildarea2(), buildarea3(), buildarea4(), buildarea4b(), buildarea5(), buildarea6(), buildarea7(), and ST_BuildArea().

1407 {
1408  GEOSGeometry* geos_in;
1409  GEOSGeometry* geos_out;
1410  LWGEOM* geom_out;
1411  int SRID = (int)(geom->srid);
1412  int is3d = FLAGS_GET_Z(geom->flags);
1413 
1414  /* Can't build an area from an empty! */
1415  if ( lwgeom_is_empty(geom) )
1416  {
1417  return (LWGEOM*)lwpoly_construct_empty(SRID, is3d, 0);
1418  }
1419 
1420  LWDEBUG(3, "buildarea called");
1421 
1422  LWDEBUGF(3, "ST_BuildArea got geom @ %p", geom);
1423 
1424  initGEOS(lwnotice, lwgeom_geos_error);
1425 
1426  geos_in = LWGEOM2GEOS(geom, 0);
1427 
1428  if ( 0 == geos_in ) /* exception thrown at construction */
1429  {
1430  lwerror("First argument geometry could not be converted to GEOS: %s", lwgeom_geos_errmsg);
1431  return NULL;
1432  }
1433  geos_out = LWGEOM_GEOS_buildArea(geos_in);
1434  GEOSGeom_destroy(geos_in);
1435 
1436  if ( ! geos_out ) /* exception thrown.. */
1437  {
1438  lwerror("LWGEOM_GEOS_buildArea: %s", lwgeom_geos_errmsg);
1439  return NULL;
1440  }
1441 
1442  /* If no geometries are in result collection, return NULL */
1443  if ( GEOSGetNumGeometries(geos_out) == 0 )
1444  {
1445  GEOSGeom_destroy(geos_out);
1446  return NULL;
1447  }
1448 
1449  geom_out = GEOS2LWGEOM(geos_out, is3d);
1450  GEOSGeom_destroy(geos_out);
1451 
1452 #if PARANOIA_LEVEL > 0
1453  if ( geom_out == NULL )
1454  {
1455  lwerror("%s [%s] serialization error", __FILE__, __LINE__);
1456  return NULL;
1457  }
1458 
1459 #endif
1460 
1461  return geom_out;
1462 }
void lwnotice(const char *fmt,...)
Write a notice out to the notice handler.
Definition: lwutil.c:177
uint8_t flags
Definition: liblwgeom.h:396
char lwgeom_geos_errmsg[LWGEOM_GEOS_ERRMSG_MAXSIZE]
#define LWDEBUG(level, msg)
Definition: lwgeom_log.h:83
int32_t srid
Definition: liblwgeom.h:398
void lwgeom_geos_error(const char *fmt,...)
#define FLAGS_GET_Z(flags)
Macros for manipulating the 'flags' byte.
Definition: liblwgeom.h:139
GEOSGeometry * LWGEOM2GEOS(const LWGEOM *lwgeom, int autofix)
LWPOLY * lwpoly_construct_empty(int srid, char hasz, char hasm)
Definition: lwpoly.c:159
LWGEOM * GEOS2LWGEOM(const GEOSGeometry *geom, char want3d)
int lwgeom_is_empty(const LWGEOM *geom)
Return true or false depending on whether a geometry is an "empty" geometry (no vertices members) ...
Definition: lwgeom.c:1386
#define LWDEBUGF(level, msg,...)
Definition: lwgeom_log.h:88
void lwerror(const char *fmt,...)
Write a notice out to the error handler.
Definition: lwutil.c:190
GEOSGeometry * LWGEOM_GEOS_buildArea(const GEOSGeometry *geom_in)

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